Glucose-6-phosphate dehydrogenase

Definition

Glucose-6-phosphate dehydrogenase (G6PD) is a type of protein, called an enzyme, that helps red blood cells work properly. The G6PD test looks at the amount (activity) of this substance in a patient's red blood cells.

Alternative Names

RBC G6PD test; G6PD screen

How the Test is Performed

A blood sample is needed. For information on how this is done, see: Venipuncture

How to Prepare for the Test

No special preparation is usually necessary.

How the Test Will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

Your doctor may order this test if you have signs of G6PD deficiency. This means you do not have enough G6PD activity.

Too little G6PD activity leads to the destruction of red blood cells. This process is called hemolysis. When this process is actively occurring, it is called a hemolytic episode.